Why can materials management be considered a balancing act? 19. What are metrics? What are their uses? 20. A computer carrying case and a backpack are familiar items to a student of manufacturing planning and control. Discuss the manufacturing planning and control activities involved in producing a variety of these products. What information from other departments is necessary for manufacturing planning and control to perform its function? 21. Describe at least three supply chains that provide products to your school book store. Do they use cooperative supply chain methods to help reduce their costs? 22. From the bookstore example in question 21, describe how one of the supply chains would use a supply chain "channel master. 23. Which manufacturing strategies are used in a fast-food business? How does this affect the lead time from the customers' point of view? 24. Give an example of a postponement activity.